As is well known, such service panels carry various electrical components such as relays, warning or indicating lamps, the control centre or flasher unit for the direction indicators, fuses, or other similar accessories. For this purpose, these various components are connected together as appropriate by means of an electrical interconnecting grid or network. The service panel has an electrical supply zone through which current passes to the grid, the latter being carried on the service panel.
In an automotive vehicle, the driver commonly has at his disposal a number of control functions provided by at least one independent electrical switching means which is mechanically fixed on a support which is separate from the service panel. Such a switch is connected by means of cables to the wiring harness of the vehicle as well as to the service panel. It may for example include at least one switch of the kind in which the functions of control of the headlamps and of the direction indicators are combined, this combination being in some applications provided with indicator lamps.
Interruptors may also be placed and secured on the dash of the vehicle, for example the hazard warning control switch, these interruptors being again connected to the wiring harness of the vehicle and to the service panel. All of this tends to result in the occurrence of voltage surges and also a somewhat complicated assembly operation, since such an arrangement involves both mechanical assembly operations and electrical connection operations. The electrical connections require a certain number of junctions, between the service panel and the electrical supply sources or the control elements; between the service panel and the apparatus to be controlled; and between the latter and the supply sources or the control elements. In addition, some connections are necessary between one item of the apparatus to be controlled and another.